Prognosis

Median survival in patients with polycythemia vera (PV), which is 1.5-3 years in the absence of therapy, has been extended to approximately 14 years overall, and to 24 years for patients younger than 60 years of age, because of new therapeutic tools.
[32] However, according to a study of Surveillance, Epidemiology and End Results (SEER) data, mortality in PV patients is higher than in an age- and sex-matched population. Five-year survival in the overall cohort was 79.5% but patients are at a high risk of second primary malignancies and leukemic transformation, which may compromise long-term survival.
[33]

The major causes of morbidity and mortality are as follows:

Thrombosis has been reported in 15-60% of patients, depending on the control of their disease. It is the major cause of death in 10-40% of patients. Venous and arterial thromboses have resulted in pulmonary emboli, renal failure from renal vein or artery thrombosis, intestinal ischemia from mesenteric vein thromboses, or peripheral arterial emboli.

Hemorrhagic complications occur in 15-35% of patients and lead to death in 6-30% of these patients. Bleeding is usually the consequence of vascular compromise resulting from ischemic changes from thrombosis or hyperviscosity.

Peptic ulcer disease is reported to be associated with PV at a 3- to 5-fold higher rate than that of the general population. This has been attributed to increased histamine serum levels.

Myelofibrosis and pancytopenia occur in 3-10% of patients, usually late in the disease, which is considered the spent phase of PV. In these patients, infections and bleeding complications may be the most serious health threats, and red blood cell transfusions may be required to maintain adequate red blood cell counts and to improve fatigue and other anemia-related symptoms.

Acute leukemia or a myelodysplastic syndrome develops in 1.5% of patients treated with phlebotomy alone. The transformation risks increase to 13.5% within 5 years with treatment using chlorambucil and to 10.2% within 6-10 years in patients treated with phosphorus-32. At 15 years, the transformation risk for patients treated with hydroxyurea is 5.9%, which, although not statistically significant, is a worrisome trend.

Abdulkarim et al studied the long-term (15 years) rate of transformation to acute myelogenous leukemia (AML) in Swedish and French patients with Ph– MPD, including 317 with PV. The annual rate of AML transformation was 0.38% in patients with PV, and the average time from PV diagnosis to AML transformation was 88 +/- 56 months. Notably, 17 of the 18 patients with PV whose condition transformed to AML were females, despite the fact that almost half of the patients with PV were males.
[34]

Bone marrow film at 100X magnification demonstrating hypercellularity and increased number of megakaryocytes. Courtesy of U. Woermann, MD, Division of Instructional Media, Institute for Medical Education, University of Bern, Switzerland.

Blood film at 400X magnification demonstrating polyglobulia and thrombocytosis. Courtesy of U. Woermann, MD, Division of Instructional Media, Institute for Medical Education, University of Bern, Switzerland.

This blood film at 10,000X magnification shows a giant platelet and an eosinophil. Erythrocytes show signs of hypochromia as a result of repeated phlebotomies. Courtesy of U. Woermann, MD, Division of Instructional Media, Institute for Medical Education, University of Bern, Switzerland.